1. Field of the Invention
This invention relates to continuous casting and, more particularly, to an apparatus for continuous casting of metals by drawing-up.
The present machine is preferably utilized for the production of hollow castings of cast-iron, steel and other metals and alloys.
2. Description of the Prior Art
There is known an experimental continuous casting machine (cf. "Metal Mould", by A. I. Veinick, Minsk Publishers, 1972, pp. 129-132), which comprises a housing adapted to accommodate the machine's main constructional members, namely: a lifting table mounting a metal supply means for uphill feeding of molten metal into the mould cavity. The metal supply means is basically a rigid metal moulding box packed with a refractory mixture with ingates and accommodating two water-cooled moulds for forming hollow castings. There is also provided a dummy bar adapted to start the withdrawal cycle.
The dummy bar is basically a hollow steel member with the exterior shape thereof conforming to that of the mould cavity; this dummy bar is used to initiate the casting process.
The machine is also provided with a drawing-up means adapted to pull out the continuously-cast product from the moulds. This means incorporates a pair of movable clamps and a pair of fixed clamps, a shifting arm lever, a double-profile cam, a propeller shaft, a gear box, a chain drive, a double-reduction cylindrical gear and an electric motor.
The metal supply means (moulding box) is placed on the lifting table and is then connected to the moulds. The dummy bars are introduced into the moulds and the movable clamps are brought down to be engaged with the dummy bars.
After molten metal is fed into the mould cavity through the metal supply means and reaches a predetermined level, the drawing-up means is actuated to move a hollow casting upwardly by means of the movable clamps, thereby pushing it through the fixed clamps. While the movable clamps are shifted to a lower position, the fixed clamps are locked to grip the hollow castings, thereby holding them in a fixed position. As this happens, the movable clamps are brought apart to slide over the fixed hollow castings. By adjusting the arm of the lever it is possible to vary the travelling distance covered by the hollow castings during one drawing-up cycle.
However, due to the absence of a cut-off means for cutting the hollow castings into predetermined lengths, it becomes necessary to periodically stop the drawing-up means. As a result, the molten metal solidifies in the metal supply means as well as in the mould. The operating cycle is resumed only after the metal supply means and dummy bars have been changed. The continuous operation of the machine is thus disrupted, and the process does not lend itself to complete automation. From the foregoing it follows that the production efficiency of such a process is extremely low.
Moreover, the wedge-type clamps used in the casting drawing-up means cause sagging in the hollow castings to occur during the drawing-up cycle with the resultant shrinkage cavities and crackings taking place in the continuously drawn-up casting.